As is known, electrodes have been used to monitor and record neural activity. For example, these electrodes may take the form of a stiff and sharpened insulated metallic wire, or a drawn glass pipette filled with an aqueous conductor. The electrode or an array of electrodes is inserted through the pia or the dura and positioned in the target neurons in the brain to record neural activity. While functional for their intended purpose, these prior electrodes have certain limitations. By way of example, over time, the brain may respond to exposure to the electrode by electrically insulating the device. Further, there may be a loss of neural activity do to neuronal death around the device. Hence, the devices may not remain functional for extended periods of time.
It can be appreciated that the development of a neural interface that provides reliable and stable long-term implant function could be used in a wide variety of applications. For example, in cases of spinal cord injury, the brain of the individual may still function to generate motor signals that would normally be conveyed to the muscles. As such, it is contemplated to monitor these motor signals within the brain of a paralyzed individual and transmit such signals to an extension device that drives an individual's muscles or an extracorporeal device and bypass the injured spinal cord. However, in order to continually monitor localized brain activity, the development of a neural interface that provides reliable and stable long term implant functionality is necessary.
A neural interface device that is intended for successful long-term implantation in the nervous system must meet a strict series of criteria in the electrical, mechanical, and biological arenas. Electrically, the devices must maintain its appropriate insulating and conductive properties over extended implant durations in an intracranial environment. Mechanically, the device must be capable of withstanding any possible micro motion with the brain tissue during implantation. Biologically, the device must maintain a biocompatible profile that does not induce an excessive foreign body or immune response.
Therefore, it is a primary object and feature of the present invention to provide a neural probe array for subdural implantation that records intracranial field potentials in a brain.
It is a still further object and feature of the present invention to provide a neural probe array for subdural implantation that is more biocompatible than prior intracortical neural interfaces.
It is a still further object and feature of the present invention to provide a neural probe array for subdural implantation that is simple and inexpensive to manufacture.
It is a still further object and feature of the present invention to provide a neural probe array for subdural implantation that can be implanted in patients for a considerably longer period of time than conventional electrodes.
In accordance with the present invention, a neural probe array is provided for subdural implantation. It is intended that the neural probe array record intracranial field potentials in a brain. The neural probe array includes a base having first and second sides and a plurality of apertures extending therebetween. A plurality of contacts are spaced along the first side of the base for recording the field potentials.
The base includes a first layer having a first outer surface defining the first side of the base and a second inner surface. The base also includes a second layer having a first outer surface defining a second side of the base and a second inner surface bonded to the inner surface of the first layer. It is contemplated for the first and second layers to be formed from insulators. A plurality of conductors are disposed between the first and second layers of the base. Each conductor has a first end operatively connected to a corresponding one of the plurality of contacts and a second opposite end operatively connected to a connector spaced from the base.
The plurality of apertures through the base may be arranged in rows and columns. Similarly, the plurality of contacts on the first side of the base may be arranged in rows and columns. Each of the plurality of contacts has a diameter in the range of 200 microns to 2 millimeters. Further, each of the plurality of contacts is spaced from an adjacent contact by a minimum distance of 300 microns.
In accordance with a further aspect of the present invention, a neural probe array is provided for subdural implantation. It is intended for the neural probe array to record field potentials in a brain. The neural probe array includes a porous base having first and second sides. A plurality of contacts are spaced along the first side of the base for recording the field potentials.
The base includes a plurality of apertures therethrough. The apertures are arranged in rows and columns. Similarly, the plurality of contacts along the first side of the base may be arranged in rows and columns. The neural probe array may also include a plurality of conductors. Each conductor has a first end operatively connected to the corresponding one of the plurality of contacts and a second opposite end operatively connected to a connector spaced from the base. A portion of each of the plurality of contactors is disposed within the base.
In accordance with a further aspect of the present invention, a neural probe array is provided for subdural implantation. It is intended for the neural probe array to record intracranial field potentials in a brain. The neural probe array includes a first layer having a first outer surface and a first inner surface and a plurality of apertures therethrough. The neural probe array further includes a second layer having a second outer surface, a second inner surface bonded to the first inner surface of the first layer, and a plurality of apertures therethrough. The plurality of apertures through the second layer are axially aligned with the plurality of apertures in the first layer. A plurality of contacts are spaced along the first outer surface of the first layer for recording the field potentials. A plurality of conductors are also provided. Each conductor has at least a portion disposed between the first and second layers, a first end operatively connected to a corresponding one of the plurality of contacts, and a second opposite end.
The plurality of contacts of the neural probe array may be arranged in rows and columns along the outer surface of the first layer. Each of the plurality of contacts has a diameter in a range of 200 microns to 2 millimeters and is spaced from an adjacent contact by a minimum distance of 300 microns. It is also contemplated to arrange the plurality of apertures through the first layer in rows and columns.